1. Field of the Invention
This invention relates generally to the testing of electronic and, logic circuits and more particularly, to the testing of devices used for circuit interconnections.
2. Description of the Related Art
In order to provide the interconnection between portions of electronic and logic systems, the recent trend has been to use standardized connectors. While the standardization of the system connectors has provided decreased cost, the diversity of potential applications has resulted in the degradation of performance in some of the applications. For example, the connectors can be involved in distribution of power in the system, in the coupling of components implemented in transistor to transistor logic (TTL), in distribution of signals in communication networks, etc. It will be clear that each type of connector can have different characteristics (e.g., impedance characteristics) depending on the application of the connector. Similarly, different applications can impose different requirements for contact interrupts of the connectors. A one millisecond interrupt in a power distribution system can, because of the signal filtering, be unimportant to the system, while a similar interrupt in transmission of TTL signals can have important circuit implications.
The contacts in the interconnect apparatus have interrupt events that can occur during the test and qualification phases or during the actual operation of the system. One class of contact interruption events occurs when a contact is tested for a duration greater than one hundred hours. The contact system is subject to change over this period of time because of relatively slow changes in the electrical properties. This class of change in the contact system can best be characterized by a change in the direct current (DC) resistance of the interconnection device and the DC resistance parameter can be readily measured, including measurement by automated systems.
A second class of contact interruption events is caused by mechanical shock and vibration. The contact interrupts detected during testing for this class of events appear to be random with respect to a time coordinate. These interrupt events can be correlated to an external stimulus such as a particular frequency imposed during vibrational contact system testing. The duration of the contact interrupt events in the second class is found to be dependent on such factors as the mechanical construction of the contact system and the amount and frequency of the vibrational energy applied to the interconnection system during the test. The durations of contact interruptions encountered during this type of testing procedure can range from 15 to 20 nanoseconds (ns) to several milliseconds (ms).